A. Field of the Invention
The present invention is directed to a unit dose comprising an FGF or an angiogenically active fragment or mutein thereof for inducing cardiac angiogenesis in a human. The present invention is also directed to a pharmaceutical composition comprising the unit dose of the FGF and to a method for administering this pharmaceutical composition to a human to induce cardiac angiogenesis while minimizing systemic risk to the patient. The present invention is useful because the unit dose, pharmaceutical composition and the method for its administration provide an alternative to surgical intervention for the treatment of coronary artery disease (CAD) and may further provide an adjunct for reducing post myocardial infarct (MI) injury in humans.
B. Background of the Invention
The fibroblast growth factors (FGF) are a family of at least eighteen structurally related polypeptides (named FGF-1 to FGF-18) that are characterized by a high degree of affinity for proteoglycans, such as heparin. The various FGF molecules range in size from 15-23 kD, and exhibit a broad range of biological activities in normal and malignant conditions including nerve cell adhesion and differentiation [Schubert et al., J. Cell Biol. 104:635-643 (1987)]; wound healing [U.S. Pat. No. 5,439,818 (Fiddes)]; as mitogens toward many mesodermal and ectodermal cell types, as trophic factors, as differentiation inducing or inhibiting factors [Clements, et al., Oncogene 8:1311-1316 (1993)]; and as an angiogenic factor [Harada, J. Clin. Invest., 94:623-630 (1994)]. Thus, the FGF family is a family of pluripotent growth factors that stimulate to varying extents fibroblasts, smooth muscle cells, epithelial cells and neuronal cells.
When FGF is released by normal tissues, such as in fetal development or wound healing, it is subject to temporal and spatial controls. However, many of the members of the FGF family are also oncogenes. Thus, in the absence of temporal and spatial controls, they have the potential to stimulate tumor growth by providing angiogenesis.
Coronary artery disease (atherosclerosis) is a progressive disease in humans wherein one or more coronary arteries gradually become occluded through the buildup of plaque. The coronary arteries of patients having this disease are often treated by balloon angioplasty or the insertion of stents to prop open the partially occluded arteries. Ultimately, these patients are required to undergo coronary artery bypass surgery at great expense and risk. It would be desirable to provide such patients with a medicament that would enhance coronary blood flow so as to preclude the need to undergo bypass surgery.
An even more critical situation arises in humans when a patient suffers a myocardial infarction, wherein one or more coronary arteries or arterioles becomes completely occluded, such as by a clot. There is an immediate need to regain circulation to the portion of the myocardium served by the occluded artery or arteriole. If the lost coronary circulation is restored within hours of the onset of the infarction, much of the damage to the myocardium that is downstream from the occlusion can be prevented. The clot-dissolving drugs, such as tissue plasminogen activator (tPA), streptokinase, and urokinase, have been proven to be useful in this instance. However, as an adjunct to the clot dissolving drugs, it would also be desirable to also obtain collateral circulation to the damaged or occluded myocardium by angiogenesis.
Accordingly, it is an object of the present invention to provide a medicament and a mode of administration that provides human patients with cardiac angiogenesis during coronary artery disease and/or post acute myocardial infarction. More particularly, it is a further object of the present invention to provide a therapeutic dose of a mammalian FGF and a mode of administration to humans that provide the desired property of cardiac angiogenesis, while minimizing adverse effects.
Many of the various FGF molecules have been isolated and administered to various animal models of myocardial ischemia with varying and often times opposite results. According to Battler et al., xe2x80x9cthe canine model of myocardial ischemia has been criticized because of the abundance of naturally occurring collateral circulation, as opposed to the porcine model, which xe2x80x98excelsxe2x80x99 in its relative paucity of natural collateral circulation and its resemblance to the human coronary circulation.xe2x80x9d Battler et al., xe2x80x9cIntracoronary Injection of Basic Fibroblast Growth Factor Enhances Angiogenesis in Infarcted Swine Myocardium,xe2x80x9d JACC, 22(7): 2001-6 (December 1993) at page 2002, col. 1. However, Battler et al., who administered bovine bFGF (i.e., FGF-2) to pigs in a myocardial infarct model, considered the varying results that are obtained from one animal species to another, and expressly discloses that the divergent results xe2x80x9cthus emphasiz[e] the caution that must be exercised in extrapolating results from different animal models.xe2x80x9d Battler et al., at page 2005, col. 1. Further, Battler points out that xe2x80x9cthe dosage and mode of administration of bFGF [i.e., bovine FGF-2] may have profound implications for the biologic effect achieved.xe2x80x9d Battler, et al., at page 2005, col. 1. Thus, it is a further object of this invention to discover a dosage and a mode of administration of a fibroblast growth factor that would provide for the safe and efficacious treatment of CAD and/or post MI injury in a human patient. More generally, it is an object of the present invention to provide a pharmaceutical composition and method for inducing angiogenesis in a human heart.
The Applicants have discovered that a fibroblast growth factor, such as of SEQ ID NOS: 1-3, 5, 8-9, or 12-14 or an angiogenically active fragment or mutein thereof, when administered as a unit dose of about 0.2 xcexcg/kg to about 36 xcexcg/kg into one or more coronary vessels (IC) of a human patient in need of coronary angiogenesis, unexpectedly provides the human patient with a rapid and therapeutic cardiac angiogenesis sufficient to obviate surgical intervention and results in an unexpectedly superior increase in the treated patient""s exercise tolerance time (ETT). By way of comparison, angioplasty is considered a therapeutic success if it provides an increase in a patient""s ETT of greater than 30 seconds compared to the placebo. By the term xe2x80x9ccardiac angiogenesisxe2x80x9d or xe2x80x9ccoronary angiogenesis,xe2x80x9d as used herein, is meant the formation of new blood vessels, ranging in size from capillaries to arterioles which act as collaterals in coronary circulation.
FGFs that are suitable for use in the present invention include human FGF-1 (SEQ ID NO: 1), bovine FGF-1 (SEQ ID NO: 2), human FGF-2 (SEQ ID NO: 3), bovine FGF-2 (SEQ ID NO: 5), human FGF-4 (SEQ ID NO: 8), human FGF-5 (SEQ ID NO: 9), human FGF-6 (SEQ ID NO: 10), human FGF-8 (SEQ ID NO: 12), human FGF-9 (SEQ ID NO: 13) and human FGF-98 (SEQ ID NO: 14). In one embodiment, FGF molecules are human FGF-1 (SEQ ID NO: 1), bovine FGF-1 (SEQ ID NO: 2), human FGF-2 (SEQ ID NO: 3), bovine FGF-2 (SEQ ID NO: 5), human FGF-4 (SEQ ID NO: 8) and human FGF-5 (SEQ ID NO: 9). In an alternative embodiment, the FGF molecules are human FGF-6 (SEQ ID NO: 10), murine FGF-8 (SEQ ID NO: 12), human FGF-9 (SEQ ID NO: 13) or human FGF-98 (SEQ ID NO: 14).
Typically, the angiogenically active fragments of the present invention retain the distal two thirds of the mature FGF molecule (i.e., the two thirds of the molecule at the carboxy end that have the cell binding sites). For convenience, the terms xe2x80x9chuman FGF,xe2x80x9d xe2x80x9cbovine FGFxe2x80x9d and murine FGF are used herein in abbreviated form as xe2x80x9chFGF,xe2x80x9d xe2x80x9cbFGFxe2x80x9d and xe2x80x9cmFGF,xe2x80x9d respectively.
The Applicants also discovered that a single unit dose of an FGF or an angiogenically active fragment thereof, when administered as a unit dose into one or more coronary vessels (IC) of a human patient in need of coronary angiogenesis (e.g., a human patient with coronary artery disease despite optional medical management), unexpectedly provides the human patient with a therapeutic benefit that is seen as early as two weeks after the single unit dose is administered (as reflected in symptoms), and that lasts at least 60 days after the single unit dose is administered (as reflected in ETT and the xe2x80x9cSeattle Angina Questionnairexe2x80x9d (SAQ)). For example, when 28 human patients diagnosed as having CAD were assessed by the SAQ both before and 57 days after being administered IC a single unit dose of 0.33 xcexcg/kg to 48 xcexcg/kg of FGF-2 of SEQ ID NO: 5, the mean increase in their scores on the five criteria assessed ranged from 13 to 36 points, which is about 1.6-4.5 times greater than the 8 point change which was considered to be xe2x80x9cclinically significantxe2x80x9d in alternative modes of treatment. See Table 2. When the scores of the 15 first patients were broken down between those receiving a low dose (less than 2 xcexcg/kg) and those receiving a higher dose (greater than or equal to 2 xcexcg/kg) of FGF-2 of SEQ ID NO: 5, and assessed by the SAQ, both doses were found to provide scores that had xe2x80x9cclinically significantxe2x80x9d increases ranging from 12.3 to 58.1 and 10.9 to 32.1, respectively. Thus, whether the patients were administered the lower doses or the higher doses of the invention, their increased scores were about 1.4-7.2 times greater than the 8 point change which was considered to be xe2x80x9cclinically significantxe2x80x9d in alternative modes of treatment. See Table 3.
As part of this study, MRI was performed on 23 human patients diagnosed with CAD to assess ejection fraction, regional myocardial function and perfusion (delayed arrival zone). The patients were administered IC a single unit dose of 0.33 xcexcg/kg to 12 xcexcg/kg of FGF-2 of SEQ ID NO: 5. Their cardiac and coronary functions were objectively assessed by magnetic resonance imaging (MRI) both before and after treatment. The MRI results demonstrated significant improvement in regional wall motion (%) and wall thickening (%) during systole. The results also showed a significant reduction in the delayed arrival zone (% LV). The results did not demonstrate any significant change in ejection fraction (EF). Thus, the Applicants have demonstrated the clinical efficacy in humans of a single unit dose of an FGF when administered IC in accordance with the present invention.
Accordingly, in one aspect, the Applicants"" invention is directed to a unit dose of FGF comprising a safe and therapeutically effective amount of an FGF of any one of SEQ ID NOS: 1-3, 5, 8-10 or 12-14 or an angiogenically active fragment or mutein thereof. Typically, the safe and therapeutically effective amount comprises about 0.2 xcexcg/kg to about 36 xcexcg/kg of an FGF of any one of SEQ ID NOS: 1-3, 5, 8-10 or 12-14 or an angiogenically active fragment or mutein thereof. In other embodiments, the safe and therapeutically effective amount of the unit dose comprises 0.2 xcexcg/kg to 2.0 xcexcg/kg, 2.0 xcexcg/kg to 20 xcexcg/kg or 20 xcexcg/kg to 36 xcexcg/kg of an FGF of any one of SEQ ID NOS: 1-3, 5, 8-10 or 12-14 or an angiogenically active fragment or mutein thereof. Expressed in absolute terms for the majority of human CAD patients, the unit dose of the present invention comprises 0.008 mg to 6.1 mg, more typically 0.3 mg to 3.5 mg, of the FGF of any one of SEQ ID NOS: 1-3, 5, 8-10 or 12-14 or an angiogenically active fragment or mutein thereof.
In another aspect, the present invention is directed to a pharmaceutical composition comprising a safe and therapeutically effective amount of an FGF or an angiogenically active fragment or mutein thereof, and a pharmaceutically acceptable carrier. Typically, the safe and therapeutically effective amount of an FGF comprises about 0.2 xcexcg/kg to about 36 xcexcg/kg of an FGF of any one of SEQ ID NOS: 1-3, 5, 8-10 or 12-14 or an angiogenically active fragment or mutein thereof, and a pharmaceutically acceptable carrier. In other embodiments of the pharmaceutical composition, the safe and therapeutically effective amount of an FGF comprises 0.2 xcexcg/kg to 2 xcexcg/kg, 2 xcexcg/kg to 20 xcexcg/kg or 20 xcexcg/kg to 36 xcexcg/kg of an FGF, such as an FGF of any one of SEQ ID NOS: 1-3, 5, 8-10 or 12-14 or an angiogenically active fragment or mutein thereof, and a pharmaceutically acceptable carrier.
In yet another aspect, the present invention is directed to a method of using the above described unit dose or pharmaceutical composition to treat a human patient for CAD or to induce coronary angiogenesis therein. The method comprises administering into one or more coronary vessels of a human patient in need of treatment for coronary artery disease (or in need of angiogenesis) a safe and therapeutically effective amount of a recombinant FGF or an angiogenically active fragment or mutein thereof. Typically, a portion of the safe and therapeutically effective amount is administered to each of two coronary vessels. More typically, the safe and therapeutically effective amount comprises about 0.2 xcexcg/kg to about 36 xcexcg/kg of an FGF of any one of SEQ ID NOS: 1-3, 5, 8-10 or 12-14 or an angiogenically active fragment or mutein thereof in a pharmaceutically acceptable carrier. In other embodiments, the safe and therapeutically effective amount comprises 0.2 xcexcg/kg to 2 xcexcg/kg, 2 xcexcg/kg to 20 xcexcg/kg or 20 xcexcg/kg to 36 xcexcg/kg of the FGF of any one of SEQ ID NOS: 1-3, 5, 8-10 or 12-14 or an angiogenically active fragment or mutein thereof in a pharmaceutically acceptable carrier.
Because FGF is a glycosoaminoglycan (e.g., heparin) binding protein and the presence of a glycosoaminoglycan (also known as a xe2x80x9cproteoglycanxe2x80x9d or a xe2x80x9cmucopolysaccharidexe2x80x9d) optimizes activity and AUC, the IC dosages of the FGF of the present invention typically are administered within 20 minutes of the IV administration of a glycosoaminoglycan, such as a heparin.